Internetwork Design Guide -- SNA Host Configuration for SRB Networks

From DocWiki

When designing source-route bridging (SRB) internetworks featuring routers and IBM Systems Network Architecture (SNA) entities, you must carefully consider the configuration of SNA nodes as well as routing nodes. This article provides examples that focus on three specific SNA devices:

Figure: Typical SNA host environment

FEP Configuration

The parameters listed in Table: BUILD Definition Parameters through Table: FEP Logical Unit (LU) Definition Parameter illustrate input to the Network Control Program (NCP) system generation process that runs in the host processor using the Network Definition Facility (NDF). The NDF is part of the ACF/NCP/System Support Program utility. The output produced by the generation process is a load module that runs in an FEP. Its typical size can be slightly under one MB to more than three MB. The ACF/NCP/System Support Program utility is also used for loading and dumping an FEP.

(Version 5.R4 and later only.) Parameters specify a receiver acknowledgement/timer(T2) for local and remote Token Rings whether from peripheral or subarea nodes. Acceptable values: localt2 range is 0 to 2.0 seconds; remott2 range is 0 to 2.0 seconds; N3 range is 1 to 127 (default is 2). The values for localt2 and remott2 should be 10.0 percent of the value of the adjacent stations's T1 timer. N3 specifies the maximum number of I-frames received without sending an acknowledgment for subarea connections.

The LUDRPOOL definition shown in Table: LUDRPOOL Definition Parameters specifies the number of peripheral resources required for the correct amount of control block storage to be reserved for new connections.

V5.4 parameter; see BUILD parameters in [[Internetwork Design Guide -- SNA Host Configuration for SRB Networks#Table 1Table: ; can be defined in LINE definition only if a subarea node was defined in GROUP definition

MAXTSL

2044 to 16732

Specifies maximum data in bytes that NTRI can transmit; TIC1 maximum is 2044; TIC2 maximum at TRSPEED16 is 16732

PORTADD

Number

For association of physical to logical ECLTYPEs; matches physical or logical ECLTYPE specification

RETRIES

m, t, n, ml

Where m = number of retries for remote ring sessions, t = pause between retry sequence, n = number of retry sequences, and ml = number of retries in a sequence for local ring sessions

Table: FEP Logical Unit (LU) Definition Parameter

Parameter

Example, Parameter Value, or Range

Parameter Description and Implementation Notes

LOCADDR

0

Specify this response only

VTAM-Switched Major Node Definitions

Devices that are attached to Token Ring and communicate with an IBM host application must be defined via the VTAM access method associated with the host. These devices are seen as dial-in resources from the host side and are defined in a configuration component named Switched Major Node. Some common definitions used in network configurations are outlined in Table: VBUILD Definition Parameter through Table: VTAM LU Definition Parameter.

Table: VBUILD Definition Parameter

Parameter

Example, Parameter Value, or Range

Parameter Description and Implementation Notes

TYPE

SWNET

Specifies a type of resource for VTAM; SWNET indicates switched major node type

Table: VTAM PU Definition Parameters

Parameter

Example, Parameter Value, or Range

Parameter Description and Implementation Notes

IDBLK

017

Typical values:

017 = 3X74

05D = PC-base VTAM PU

0E2 = Cisco SDLLC (registered with IBM)

IDNUM

xxxxx

Unique number identifying a device

MAXOUT

1 to 7

Number of I-frames sent before acknowledgment is required

MAXDATA

265

Indicates maximum number of bytes a PU 2 device can receive; ignored for PU 2.1, as this value is negotiable

Default for 3174 is 521

PUTYPE

2

Only valid value

XID

YES or NO

YES should be used for PU 2.1 devices

NO should be specified for any other device

Table: VTAM LU Definition Parameter

Parameter

Example, Parameter Value, or Range

Parameter Description and Implementation Notes

LOCADDR

2 through FF

Logical unit (LU) addresses attached to a PU

3174 Cluster Controller Configuration Example

The following configuration was taken from 3174-13R cluster controller serial number 45362 connected to a Token Ring. These entries were used with a specific 3174 running on a 4-Mbps Token Ring. The configuration of this 3174-13R involved three specific configuration screens. Table: 3174-13R Screen 1 Configuration Details through Table: 3174-13R Screen 3 Configuration Details list the configuration line numbers, entries used, and descriptions of the configuration line. When applicable, extended descriptions are included for configuration entries that are relevant to the requirements of the routed internetwork.

Note:

Of particular interest when configuring 3174 devices for a router-based SRB environment are configuration line items 106, 107, and 384 in configuration screen 2 (refer to Table: VTAM LU Definition Parameter). These specify the required addresses and relevant Token Ring type for the cluster controller.

Table: 3174-13R Screen 1 Configuration Details

Configuration Line Number

Sample Value

Parameter Description and Implementation Notes

98

Online test password

99

TKNRNG

Description field

100

13R

Model number

101

7

Host attachment type

Table: 3174-13R Screen 2 Configuration Details

Configuration Line Number

Sample Value

Parameter Description and Implementation Notes

106

4000 2222 4444 04

The first 12 hexadecimal digits form the source MAC address of the cluster controller (4000 2222 4444); the last two digits are the source SAP (SSAP) for LLC2 (0x04 = SNA).

107

4000 0037 4501 04

The first 12 hexadecimal digits form the destination MAC address of the FEP (4000 0037 4501); the last two digits are the DSAP for LLC2 (0x04 for SNA).

108

0045362

Serial number of the cluster controller

110

0

MLT storage support

116

0

Individual port assignment

121

01

Keyboard language

123

0

Country extended code page support

125

00000000

Miscellaneous options (A)

126

00000000

Miscellaneous options (B)

127

0 0

RTM definition

132

0000

Alternate base keyboard selection

136

0000

Standard keyboard layout

137

0000

Modified keyboard layout

138

0

Standard keypad layout

141

A

Magnetic character set

165

0

Compressed program symbols

166

A

Attribute select keypad

168

0

Additional extension; mode key definition

173

0000

DFT options

175

000000

DFT password

179

000

Local format storage

213

0

Between bracket printer sharing

215

45362

PU identification

222

0

Support for command retry

382

0521

Maximum ring I-frame size; range of values is 265 to 2057.

383

2

Maximum number of I-frames 3174 will transmit before awaiting an acknowledgment (transmit window size).